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What should I notice when using optical fibers

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Introduction to optical fibers:

The connector type of an optical fiber is the same as the interface type of the optical module to which the optical fiber is connected. Connector types of optical fibers include LC, SC, FC, ST, MU, and MPO. LC connectors are most widely used.

Optical fibers are classified into multimode and single-mode optical fibers:

- Most of multimode optical fibers are orange, but a few multimode optical fibers are other colors. For example, optical fibers with MPO connectors are light green. Multimode optical fibers can be used with multimode optical modules to implement low-cost, short-distance transmission.
- Single-mode optical fibers are yellow. They can be used with single-mode optical modules to implement long-distance transmission.

Precautions for using optical fibers:

- The bend radius of optical fibers must be larger than the minimum bend radius allowed by the optical fibers. Otherwise, the optical modules will be damaged, and quality of optical signals will degrade.
- Do not look into an optical interface without eye protection, or the laser may hurt your eyes.
- It is recommended that idle fiber connectors be covered with dust-proof caps to keep the fiber connectors clean. An unclean fiber connector may degrade the quality of optical signals or even cause link failures or error codes on the link.

Other related questions:

The followings are notes about configuring RRPP on S series switches (except S1700):
1. You need to disable STP on ports.
Note: Either RRPP or STP can be configured on a port. RRPP and STP cannot be configured synchronously. By default, ports are enabled with STP.
2. When instances are created, the major control VLAN and the sub-control VLAN must be included in the VLAN list.
Note: By default, the sub-control VLAN ID is 1 larger than the major control VLAN ID.
3. After creating instances, you must run the active region-configuration command to activate the MSTP region.
Note: Region activation is easily to be neglected. After configuring instances, use check region-configuration command to check instance configurations that have taken effect.
4. Ports added to data VLANs must be Trunk-type or Hybrid-type ports.
Note: RRPP ports need to allow packets in both control VLANs and data VLANs to pass through.
5. An RRPP port cannot be successfully added to a VLAN if RRPP snooping has been enabled on the VLANIF interface of the VLAN.
6. When control VLANs are created, the control VLAN specified by vlan-id and the sub-control VLAN specified by vlan-id plus one must be VLANs that have not been created and are not used in the configuration of VLAN mapping or VLAN stacking. In addition, no interface is added to the VLANs.
Note: The sub-control VLAN is easily to be neglected. Existence of a sub-control VLAN often causes failures of major VLAN creation. Even if a sub-ring is not needed, the sub-control VLAN whose VLAN ID is 1 larger than the VLAN ID of the major control VLAN is automatically created when the major control VLAN is created.
7. DHCP cannot be configured for an RRPP control VLAN.
8. VLANs allowed by RRPP ports need to be configured as protected VLANs, including data VLANs and control VLANs.
Note: Before configuring RRPP rings, protected VLANs must be configured. In the same physical topology, control VLANs of the local domain cannot be protected VLANs of other domains. The control VLANs must be included in the scope of protected VLANs. Otherwise, rings are not allowed to be configured. When mapping between instances and VLANs changes, the scope of protected VLANs of the RRPP domain also changes.
9. RRPP rings can be activated only when the RRPP rings and the RRPP protocol are enabled synchronously.
10. The network topology convergence speed varies with the number of configured domains and rings. Smaller number means faster convergence.
11. Due to the hardware specification limitation, resources must be allocated properly when multiple RRPP rings are configured.
For more details on RRPP configuration notes and fault location methods, click RRPP配置注意事项.